1. Field of the Invention
The invention pertains to the field of medication distribution systems. More particularly, the invention pertains to an efficient system for automatically dispensing and distributing solid medicinal units, such as pills and capsules, to patients, primarily in a hospital setting.
2. Description of Related Art
Various drug storage and dispensing devices are disclosed in the art. These devices are primarily concerned with efficient storage and dispensing of a number of pills or capsules based upon patient needs. There are few if any devices, however, directed to implementing a comprehensive, efficient, and error free means of distributing a few medicinal units to hundreds or thousands of patients simultaneouslyxe2x80x94such as in a hospital settingxe2x80x94where patients have varying medicinal needs that must be fulfilled at selected times of the day.
The invention disclosed in U.S. Pat. No. 2,577,344 is directed to a xe2x80x9cNarcotic Dispenserxe2x80x9d in which the drugs are stored in individual tubes, with a weight pressing them down, and the tubes are refilled and distributed to the dispenser. The tubes are kept side-by-side in a cabinet in which are visible all stored narcotic vials, and the number of units remaining for each. The invention contemplates use of a single cup which is manually positioned underneath the tube containing the particular narcotic to be dispensed. The apparatus does not, however, include means of automatically and simultaneously filling many cups with the medications needed by a large number of patients.
U.S. Pat. No. 5,907,493 is a xe2x80x9cPharmaceutical Dispensing Systemxe2x80x9d, for organizing a pharmacy by xe2x80x9csequentially and interactivelyxe2x80x9d instructing pharmacists in filling prescriptions. The system uses a number of dispensers, each with a microprocessor. Barcode labels are printed and applied to vials. The vials are scanned, and a xe2x80x9cready to fillxe2x80x9d light is lit on the dispenser. A microswitch detects the vial is in position, and the pills are dispensed. There is no conveyor system, and no provision to operate the system automatically for a number of vialsxe2x80x94each vial must be separately, consecutively, and manually scanned, carried to the dispenser, filled, and capped.
Due to the above-described and other limitations, it is desirable to provide a medicament-dispensing system that compactly stores hundreds or thousands of different drugs, and dispenses the drugs accurately and efficiently for hundreds of patients, primarily in a hospital setting, at selected times of the day. Such a hospital drug distribution system should minimize the possibility of human error resulting in the wrong medication being dispensed. It should also be operable in a manual mode for exceptional cases where drugs are needed at other than the selected times of the day, or where only a small number of drug orders must be filled. Such might be the case, for example, in a small nursing home. Additionally, as the number of drugs to be handled by the system grows, the system should be able to grow accordingly in an efficient and cost-effective manner. For that reason, the system should be modular, to allow for easy expansion to include an ever larger set of drugs.
This application discloses and claims an invention that is useful in conjunction with an apparatus of the type shown and described in a commonly owned U.S. application entitled, xe2x80x9cDRUG STORAGE AND DISPENSING APPARATUS,xe2x80x9d filed on the same day as the present application. That application is hereby incorporated by reference herein in its entirety.
The invention comprises a hospital drug distribution system, or HDDS, for dispensing and distributing solid medicinal units, such as pills, capsules, or the like (hereinafter, xe2x80x9cmedicinal units,xe2x80x9d or simply, xe2x80x9cunitsxe2x80x9d), automatically and efficiently, based upon patient needs. In the invented device, the medicinal units are stored in long, thin tubes, positioned vertically, side-by-side. Each tube has a valve at the bottom, with control electronics to dispense a precise number of units from the tube. The tubes are arranged, preferably, in a U-shaped arrangement, and are suspended over a conveying means which transports cups that receive the dispensed units. In the preferred embodiment, the conveying means transports the cups via cup-holding trays placed upon it, and there are nine to twelve cups per tray.
Prior to entering upon the conveying means, a cup-labeling subsystem draws data from the main computer database containing records of patients"" medicinal needs. Based upon such data, this labeling subsystem places labels on cups on the conveying means, on the way to be filled with medicaments. Each label contains barcode-encoded data including the patient""s name, location, and medicinal requirements. The label is placed by this subsystem on the side of a cup specially designed for receiving dispensed medicaments from the drug tubes. The cups are placed upon special trays and the trays conveyed upon the conveying means under each drug tube in turn, as described below.
The conveying means proceeds in a step-and-stop fashion, whereby each cup stops briefly beneath each drug tube. The progress of the cups through the system is controlled by a computer. If the cup underneath a particular drug tube pair is assigned to a patient who needs medicinal units stored in those tubes, the valve at the bottom of the active tube of the pair dispenses the required number of units into the cup. At each step, after all such dispensing has finished, the computer signals the conveying means to xe2x80x9cstep-and-stopxe2x80x9d once again, thus moving each cup to the next tube pair. The cups are arranged on the conveying means in single file such that, during any given xe2x80x98stopxe2x80x99 period, there is only one cup underneath each tube pair. In such manner, each cup begins its journey at the beginning of the conveying means, and stops underneath each tube pair for possible dispensing of medicinal units. Because multiple cups make their way upon the conveying means simultaneously (and in single-file), dispensing of drugs is efficient as it takes place for multiple patients in parallel. The process begins with the first cup stopping under the first tube pair. In the next step, the first cup stops under the second tube pair, and the second cup stops under the first tube pair, and so on. When the cups reach the end of the conveying means, a tray-removal subsystem removes the trays therefrom and places them on special carts for distribution to the patients.
In one embodiment of the invented system, there is only one such cup per patient; by the time each cup has completed its journey and stopped briefly beneath each tube pair, it contains the exact mix, or xe2x80x9ccocktail,xe2x80x9d of drugs needed by the patient to which it is assigned. In another embodiment, each cup holds only one type of medication, and hence, each patient has one or multiple cups. All cups assigned to a patient are delivered to the patient by a hospital staff member. The advantage of this one-cup-per-patient-per-medication embodiment is that, if any drugs go unused and the cups remain sealed, such unused drugs are returned to the drug refilling center for recycling into a new drug tube.
Each tube is stocked to contain a large number of units of the same medication. A valve at the bottom of each tube is specially designed for efficient dispensing of the appropriate number of medicinal units into the cup underneath it, according to data delivered to the valve""s control electronics. For each set of valves there is a barcode scanner and reader (collectively, the barcode reader), disposed adjacent to the conveying means near the valves. The barcode reader scans and reads the barcode on the cup as the cup arrives underneath the valves to which the reader is coupled. The decoder interprets the barcode and transmits the code(s) of the required drug(s) to the valves. If any such code corresponds to the code of the drug dispensed by the valve, and if the valve is in xe2x80x9cactivexe2x80x9d status, the valve dispenses the indicated number of medicinal units into the cup below. In this manner, at the end of the cup""s journey upon the conveying means, it contains the number of units of the correct drug according to its barcode label.
The system is compact in that the drug tubes are thin. The system is also modular, in that additional modules containing, say, 100 tubes, can be added or removed as needed. The system is built by adding as many modules as are needed to accommodate the number of tubes necessary to serve the patients"" medicinal needs. The tubes are preferably stored in pairs, such that there is a xe2x80x9cprimaryxe2x80x9d tube and a xe2x80x9cbackupxe2x80x9d tube for each drug in the system. When one tube runs out, the other tube is activated and becomes the primary dispensing tube. Thus, the two tubesxe2x80x94the primary and the backupxe2x80x94have a means to communicate with each other so that, when the primary becomes empty (or malfunctions), the backup takes over dispensing medicinal units. In such event, the primary tube must be replaced; this is communicated to the Control computer of the invented system.
When any given tube becomes empty, it is either discarded or sent to a drug refilling center for re-stocking, depending upon the comparative costs of tube recycling versus purchasing of new tubes. The hospital, preferably daily, orders from such center all tubes (whether recycled or purchased new) that it presently needs or anticipates needing by the following day. Such tubes are preferably ordered automatically via a computer network by a control computer, which tracks drug inventory levels within the tubes of the HDDS. The replacement tubes are preferably delivered overnight or within hours, depending upon the need, to the hospital for installation into the HDDS.